These two colors love each other and always will.  I use a lot of silver and gold toned metals, but every so often turn to copper.  It has a warmth and richness that is very appealing and in certain cases is the only metal that will do.  I used copper wire to wrap these cobalt furnace glass triangles, added opaque blue discs, shiny darker copper glass beads, and then made copper earwires to match.  How delightful.cobalt-and-copper